Esters of the thio acids of phosphorus



Patented Dec. 8, 1936 UNITED STATES PATENT OFFICE ES'IEBS OF THE 'IHIOACIDS OF PHOSPHORUS No Drawinl.

22 Claims.

This invention relates to new esters of the thio acids of phosphorus andmore particularly to the long chain aliphatic esters of such acids.

The aliphatic esters of orthophosphoric acids are known. Theorthophosphor'ic esters of the vlow molecular weight alcohols have notproved to be entirely satisfactory for commercial use for the reasonthat they do not have the marked surface active eflect desired incompounds of this type in the uses for which they are intended.

to be employed. The orthophosphoric esters of the longer chain aliphaticalcohols have the desired surface active eflect but are generally solidsat ordinary room temperatures and are insufllciently soluble in oils andhydrocarbon solvents to enable full advantage to be taken of theirdesirable properties.

An object of the present invention is to pro- .vide new chemicalcompounds having the advantageous features of prior compounds butwithout all of their disadvantages. A further object of this inventionis to provide long chain aliphatic esters of the thio acids ofphosphorus which are new chemical compounds. A still further object isto provide methods for preparing such new chemical compounds. Otherobjects are to provide new compositions of matter and to advance theart. Still other objects will appear hereinafter.

These objects may be accomplished in accordance with our invention whichcomprises reacting an esterifying derivative of a thio acid ofphosphorus with at least one molecular propor- 'tion of an aliphaticalcohol containing at least ten carbon atoms or'reacting an esteriiyingde- 45 intend to include the mono, di, tri and tetra thioortho-phosphoric acids, the thio-meta-phosphoric acids, thethio-pyrophosphoric acids, the thiohypophosphoric acids and also thethio phosphorus acids including the ortho, pyro and hypo acids. However.the thiophosphoric acids are generally the cheapest to manufacture andhave the most desirable properties and of these the thioortho-phosphoric acids are preferred both for ease and cheapness ofmanufacture and for 55 their unusually desirable properties.

. control the reaction.

Application February 19, 1935,

Serial No. 7,216

The esters of our invention contain "at least one aliphatic chain of atleast ten carbon atoms. They may contain 2, 3 or 4 of such chains. Theymay contain aliphatic chains of a lesser number of carbon atoms. Thesealiphatic chains may be derived from either saturated or unsaturatedaliphatic alcohols and are preferably hydrocarbon chains. nolicradicals. In other words, the esters of our invention may be eitherneutral or acid esters and may be homogeneous or mixed esters.

The esters of dithio ortho-phosphorlc acid may be prepared by reactingat least one molecular proportion of the desired alcohol with a mixtureof phosphorus and sulphur or with Pass. For example, two molecularproportions of dodecyl alcohol, when reacted with P285, forms didodecyldithiophosphate. An inert organic solvent such as benzene or toluene maybe employed to better The reaction will generally be carried out under areflux condenser at refluxing temperatures and under a slight vacuum inorder to remove hydrogen sulfide which is formed. If desired, thealcohol may be first reacted with sodium to form the correspondingalcoholate before reacting with the phosphorus pentasuli'lde.

The monothio ortho-phosphates may be prepared by reacting one or moremolecular proportions of the alcohol or alcoholate with phosphorussulfochloride PSCls. For example, when three molecular proportions ofsodium dodecyloxlde were reacted with PSCla, tridodecyl monothioortho-phosphate was obtained. When one molecular proportion of decylalcohol was reacted with PSCla, the mono decyl monothio phosphate wasobtained.

Still other esters of thio ortho-phosphoric acids may be prepared byreacting mercaptans such as tetradecyl mercaptan with'phosphorusoxychloride POCh. The compounds produced by this method have each alkylchain connected to the phosphorus through a sulphur atom. The resultingproduct will be a mono, di or tri-thio phosphate, depending upon themolecular proportions of the mercaptan to the phosphorus oxychloride. Ifthe phosphorus oxychloride is substituted by phosphorus penta sulphidethe tetra thio phosphate will be produced. A dithio phosphate producedby this method will be isomeric with that obtained by reacting thealcohol with phosphorus pentasulflde. It will be apparent that a varietyof esters of the thio acids of phosphorus may be obtained by employingother esterifying derivatives of the acids of phosphorus in place 0!They may also contain pheflux condenser for 18 hours.

In order to more clearly illustrate our invention and the preferredmodes of carrying the same into eflfect, the following examples aregiven Example 1 Twenty-two and two-tenths parts by weight of phosphoruspentasulflde were suspended in 258 parts by weight of toluene. To this.74.4 parts by weight of dodecyl alcohol were added slowly. The mixturewas heated at 725 mm. under a re- The resulting reaction product formsstable emulsions when mixed with water.

This reaction product was treated with the calculated amount of anilineand-heated under a vacuum to remove most of the toluene. The thick syrupwhich remained crystallized when chilled in ice water. The salt wasrecrystallized from toluene in which it is soluble at room temperatures.The White crystals were then dissolved in ether and anilinehydrochloride was precipitated by passing in dry hydrogen chloride.

The aniline hydrochloride was filtered off and the filtrate evaporated.The oily residue became solid when chilled to about 50 C. but melted toan oil when warmed up to 20 C. It did not crystallize in an ice-saltmixture. The oil was heated under a vacuum to remove residual solvents.This oil analyzed 6.3% of phosphorus. (Theory for didodecyldithiophosphate is 6.6% phosphorus.) The didodecyl dithio phosphate whenadded to water was sufliciently soluble to render. the water acid inreaction.

The p-nitroaniline salt of the dithiophosphate was prepared bydissolving it in toluene and treating with p-nitroaniline. This salt wasquite soluble in toluene and alcohol at ordinary temperatures.

The pyridine salt was prepared by adding the calculated amount ofpyridine to a water suspension of the didodecyl dithio phosphate and thesolution shaken. The resulting solution foamed and exhibited a cleansingaction when applied to the skin.

, The sodium salt of didodecyl dithio phosphate, made by treatingdidodecyl dithiophosphate with an aqueous solution of sodium carbonate,is not soluble in water.

Example 2 When four molecular proportions of 9,10-octa- .decenyl alcoholwere reacted with one molecular proportion of phosphorus pentasulfide inaccordance with the procedure of Example 1, dioctadecenyl dithioo'rtho-phosphate was produced. This compound has the formula Example 3-When five molecular proportions of octadecyl alcohol were reacted withone molecular proportion of phosphorus pentasulfide, trioctadecyl dithioortho-phosphate was obtained. This compound has the following formulaExample 4 When three molecular proportions of tetradecyl alcohol yverereacted with one molecular proportion of phosphorus sulphur chloride,tritetradecyl monothio ortho-phosphate having the formula CuHnO CuHu wasobtained.

Example 5 Monotetradecyl thiometaphosphate having the formula 0 CnHaO-Pwas obtained by treating tritetradecyl monothio ,ortho-phosphate withconcentrated sulphuric acid.

Example 6 Monocetyl monothio o-phosphate having the formula Cie aO S P110/ on was prepared by reacting one mol. of cetyl a1- cohol with onemol. of PSCla in accordance with the procedure of Example 4, .followedby hydrolysis.

Example 7 Tridodecyl trithio ortho-phosphate having the formula uas\%may be made by reacting three mols of dodecyl mercaptan with one mol. ofphosphorus oxychloride.

CnHu S I Example 8 Tridodecyl trithio phosphate CuHuS P--S u u CuHuS maybe obtained by reacting one mol. Pas: with three mols of dodecylalcohol. This compound is preferably obtained by reacting three mols oidodecyl mercaptan with phosphorus trichloride Example 9 The 0,0-dicetylmonothio ortho-phosphate CuHaS OH maple 10 The tetracetyldithiopflophowhate can-o ocunu CnHaO (Julia I may be obtained bytreating tricetyl monothiophosphate with concentrated sulphuric acid.

Example 11 dodecyl mercaptan with one mol. oi phosphorus pentasulflde.

Emmple 12 'Ietratetradecyl trithiopyrophosphate uHnO O C Ha may beobtained by, reacting four mols oi tetradecyl alcohol with one mol. oi!phosphorus trisuliotetrabromide PaSaBn.

Example 13 'lietraeicosyl penta-thiopyrophosphate CnHuO\ %S S\ /S CmHnCsvHnO S CsoHn may be obtained by reacting two mols oi eicosyl alcoholand two mols of eicosyl mercaptan with one mol. of phosphorustrisuliotetrabromide.

Example 14 One gram molecular weight of phosphorus pentasulrlde wassuspended in 2580 parts by weight of toluene. To this four grammolecular weights of the mixture 01 alcohols obtained by the carboxylicreduction of coconut ofl were added slowly. The mixture was heated at125 mm. at the reflux temperature under a reflux condenser for 18 hours.The resulting mixture of esters and mixed esters oi dithio phosphoricacid was an oil which formed stable emulsions when mixed with water.This oil blends readily with lubricating oil and in this respect oflersan advantage over a pure didodecyl dithio phosphate which blends lessreadily with lubricating oil.

The above examples are merely illustrative of some of the compoundsembraced within our invention and the preierred modes of preparing suchcompounds. Other similar compounds may be prepared from other alcoholssuch as decyl, undecenyl, hexacosyl, eleostearyl, linoleyl, ricinoleyl,abietyl and the like alcohols and mercaptans. Also, mixtures of esterscontaining mixed esters may be prepared by reacting a mixture 01' suchalcohols with an esteriiying derivative of a thio acid 01' phosphorus ora mixture of the corresponding mercaptans with an esterifying derivativeof an acid of phosphorus. When such mixtures are employed, it will, ingeneral, be desirable to employ such a mixture obtainable from thealcohols obtained by the carboxylic reduction of a natural fatty oilsuch as sperm oil and coconut-oil or the acids present therein. Othermixtures of esters comprising mixed esters may be I from the olefinsobtained by cracking paraflin wax hydrocarbons.

1! pure mixed esters are desired. they may be obtained by reacting oneor two mols of an alcohol or mixture of alcohols containing at least tencarbon atoms with the esterifying derivative of a thio acid ofphosphorus or their corresponding mercaptans with an esteriiyingderivative of an acid 01' phosphorus and then reacting the resultingproduct with one or more mols of a different alcohol, a phenol ormercaptan.

Our invention embraces the acid esters and their salts such as thealkali, alkaline earth, calcium, zinc, lead or ammonium salts. By"ammonium salts, we intend to include the salts of amines such as, forexample, monododecyl amine, diethyl amine, cyclohexylamine,triethanolamine, aniline, nitroaniline, pyridine, naphthylamine,o-toluidine, diphenyl guanidine and the like as well as the salts ofammonia.

In the above examples, we have disclosed toluene as a diluent for thereaction. We may use other inert solvents or no solvents at all. Weprefer to use a solvent which is effective tor the solution of both thealcohol and the resulting thiophosphate but which is a non-solvent forimpurities in the reagents. For example, such solvents as chlorobenzene,carbon tetrachloride, benzene and the like or mixtures of such solventssuch as a mixture 01 carbon tetrachloride and toluene will be found tobe satisfactory.

The compounds of our invention may be employed as flotation agents forthe separation of various types of minerals, or as parasiticides or asacid inhibitors in metal pickling baths or as corrosion inhibitors toretard the attack of metals by oxygen in aqueous solutions or inlubricants for bearings which operate under high pressures or asaccelerators for the vulcanization of rubber. Our compounds will haveadvantages over similar compounds for these purposes. For example,didodecyl dithiophosphate has the advantage over diai'nyldithiophosphate in that the aniline salt oi. didodecyl dithiophosphateis more soluble in hydrocarbon solvents than the aniline salt of diamyldithiophosphate. Also, the sodium salt of didodecyl is substantiallyinsoluble in water, whereas the sodium salt of diamyldithiophosphate isreadily soluble in water. The dithiophosphates are generally oils atordinary temperatures, whereas, the corresponding phosphates, such asdidodecyl o-phosphate, are solids. advantage for many technicalapplications such as their use as flotation agents, in pharmaceuticalsand as acid corrosion inhibitors. Furthermore, the sulphur content ofour compounds renders them more eflective for many technicalapplications than the corresponding phosphates containing no sulphur;for example, when employed as parasiticides, flotation agents, or asacid inhibitors. Furthermore, our compounds are more desirable asassistants for use in extreme pressure lubricants over the correspondingphosphates containing no sulphur and the lower molecular weightdithiophosphates because of their great solubility in the oils and theirhigher degree of oiliness.

While we have disclosed the preferred embodiments '0! our invention, itwill be readily apparent that many variations and modifications may beThis is an made therein without departing from the spirit of ourinvention. Accordingly, the scope of our invention is to be limitedsolely by the appended claims construed as broadly as is permissible inview of the prior art.

We claim: 7

1. An aliphatic ester of a thio-acid of phosphorus in which at least onealiphatic radical contains at least 10 carbon atoms.

2. An aliphatic ester of a thio phosphoric acid in which at least onealiphatic radical contains at least 10 carbon atoms.

3. An aliphatic ester of a thio o-phosphoric acid in which at least onealiphatic radical contains at least 10 carbon atoms.

4. An alkyl ester of a thio-acid of phosphorus in which at least onealkyl radical contains at least 10 carbon atoms.

5. An alkyl ester of a thio phosphoric acid in which at least one alkylradical contains at least 10 carbon atoms.

6. An alkyi ester of a thio-o-phosphorlc acid in which at least onealkyl radical contains at least 10 carbon atoms.

7. An aliphatic ester of a dithio-acid of phosphbrus in which at leastone aliphatic radical contains at least 10 carbon atoms.

8. An aliphatic ester of'a dithio phosphoric acid in which at least onealiphatic radical contains at least 10 carbon atoms.

9. An aliphatic ester of dithio orthophosphoric acid in which at leastone aliphatic radical contains at least 10 carbon atoms.

10. A dialiphatic ester of a thio-acid of phosphorus, each aliphaticgroup containing at least 10 carbon atoms.

11. A dialiphatic ester of a thio o-phosphoric acid, each aliphaticgroup containing at least 10 carbon atoms.

12. A dialiphatic ester oi. a dithio-acid of phosphorus, each aliphaticgroup containing at least 10 carbon atoms.

13. A dialiphatio ester of dithio o-phosphoric acid, each aliphaticgroup containing at least 10 carbon atoms.

14. A dodecyl ester of a thio-acid of phosphorus.

15. A dodecyl ester a thio o-phosphoric acid.

16. A dodecyl ester of a dithio-acid 0i phosphorus.

17. A dodecyl ester of dithio o-phosphoric acid.

18. A didodecyl ester of a thio-acid of phosphorus.

19. A didodecyl ester of a thio o-phosphoric acid.

20. A"didodecyl ester of a dithio acid of phosphorus.

21. Didodecyl dithio o-phosphoric acid.

22. Di-(9,10-octadecenyl) dithio ortho-phosphate.

PAUL L. SALZBERG. JAMES H. WERNTZ.

